1. Field of the Invention
This invention relates to a method and apparatus for analyzing information about yarn eveness.
2. Description of the Prior Art
In the case of yarn spun on a spinning frame, an individual yarn imperfection such as slub sticking to the yarn is detected during the spinning operation by a slub catcher fixed to the spinning frame. However, defects such as variation in yarn thickness are not detected during said operation. Instead, pieces of full bobbins with wound-up yarn must be sampled. Strands of yarn on said bobbins are evaluated with respect to eveness by testing apparatus such as the Uster eveness tester or spectrograph, installed on a site other than that of the spinning frame, for the purpose of testing said yarn and estimating defects in the spinning frame that has spun said yarn.
Variation in thickness of yarn is categorized into two kinds: (1) cyclic variation, caused by defects such as eccentricity or deformation of a roller or by defects in the driving system, or (2) non-cyclic variation, caused by worn-out aprons, etc. Cyclic variations produce defects such as moire patterns appearing on the woven fabric, extremely degrading the commercial value of the fabric.
So far as detection of yarn eveness depends on such methods as above, many hands are required for sampling and, further, a long period of time is required for testing by means of the Uster tester and spectrograph. Test results are low in accuracy and, even when a final analysis result is reliable, the spinning frame has been continuously driven without removal of the defect during performance of the analysis. A large quantity of imperfect irregular yarn is therefore produced under these prior art testing methods.
Said prior art testing methods are not only troublesome because of the many steps required, but are also substantially impossible to apply to a multiplicity of spindles at short intervals. This fact accounts for an increase in the risk of overlooking the production of defective yarn by using these prior art testing materials.
An objective of the present invention is to provide a yarn defect detector which detects and analyzes yarn defects as quickly as possible, so that the defective part in the spinning frame which causes the yarn defect may be detected and corrected as early as possible. A further objective is to provide such detection virtually simulataneously on a multitude of spindles.